Exhaust gas purification catalyst

Abstract

An object of the present invention is to provide an exhaust gas purification catalyst that can prevent a decrease in the exhaust gas purification performance by phosphorus poisoning, and the present invention provides an exhaust gas purification catalyst (1A), including a substrate (10) and first and second catalyst layers (20, 30) each provided on the substrate (10), wherein the second catalyst layer (30) is provided on an upside or upstream of the first catalyst layer (20), wherein the first catalyst layer (20) contains at least one selected from Pd and Pt, wherein the second catalyst layer (30) contains Rh, Al, and barium sulfate, wherein a mole ratio of a content of Al in the second catalyst layer (30) to a total content of all metal elements in the second catalyst layer (30) is 0.55 or more and 0.85 or less, and wherein a mole ratio of a content of Rh in the second catalyst layer (30) to a content of Ba in the second catalyst layer (30) is 0.0040 or more and 0.040 or less.

1 . An exhaust gas purification catalyst, comprising a substrate and first and second catalyst layers each provided on the substrate,
 wherein the second catalyst layer is provided on an upside or upstream of the first catalyst layer,   wherein the first catalyst layer comprises at least one selected from Pd and Pt,   wherein the second catalyst layer comprises Rh, Al, and barium sulfate,   wherein a mole ratio of a content of Al in the second catalyst layer to a total content of all metal elements in the second catalyst layer is 0.55 or more and 0.85 or less, and   wherein a mole ratio of a content of Rh in the second catalyst layer to a content of Ba in the second catalyst layer is 0.0040 or more and 0.040 or less.   
     
     
         2 . The exhaust gas purification catalyst according to  claim 1 , wherein the second catalyst layer comprises a γ-alumina phase. 
     
     
         3 . The exhaust gas purification catalyst according to  claim 1 , wherein the second catalyst layer further comprises at least one selected from Pd and Pt. 
     
     
         4 . The exhaust gas purification catalyst according to  claim 1 , wherein the second catalyst layer further comprises Ce, and wherein a mole ratio of a content of Ce in the second catalyst layer to a total content of all metal elements in the second catalyst layer is 0.020 or more and 0.050 or less.